JP2570405B2 - Electronic balance - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention distributes a load on a dish to a plurality of levers,
The present invention relates to an electronic balance that combines the output of each lever and transmits it to a load sensor.

<Prior art> As a mechanism of an electronic balance, a plate is supported by a roberval mechanism (parallel guide), and a lever is elastically connected to a movable portion of the roberval mechanism. The mechanism for transmitting to the sensor occupies the mainstream. Alternatively, for example, there is also a mechanism for temporarily sharing a load on a plurality of levers as shown in FIG. 4 and then combining and transmitting the load to the load sensor. In other words, in the mechanism shown in FIG. 4, the tray support R for supporting the plate D is provided with separate levers supported on the base B at both ends and the like.
L _1, L ₂ resiliently connected to the load acting on the dish D as well as simultaneously transmitted to the lever L _1, L ₂ of these plurality, these lever L _1, L ₂ mutually resiliently the The outputs (force and displacement) are combined and combined, and the combined output is transmitted to the load sensor S.

<Problems to be Solved by the Invention> By the way, in any of the mechanisms described above,
Conventionally, since it is necessary to elastically connect the respective components, the robarbal mechanism, the lever, and the like are manufactured individually by using, for example, an aluminum alloy or the like, and the elasticity of forming the lever, the point of action, the fulcrum, etc. The connecting portion is made of high elastic steel or the like, and the members are assembled by screwing, caulking, or bonding each other.

Therefore, the number of parts is large, the number of assembling steps is large, and the cost is high.Also, since different materials are used, the linear expansion coefficients of the respective parts are different, and a relative dimensional change occurs due to a temperature change, or There have been problems such as drift caused by deformation due to a bimetal effect in a connection portion between different materials.

The present inventor has already made proposals (Japanese Patent Application No. 62-113133 and Japanese Patent Application No. 62-98853) for solving the above-mentioned problems with respect to a mechanism employing a Roberval mechanism. It is an object of the present invention to solve the above-mentioned problem with respect to a mechanism of a method of sharing a load on a plate to a plurality of levers.

<Means for Solving the Problems> A configuration for achieving the above object will be described with reference to FIGS. 1 and 2 corresponding to the embodiment. The present invention relates to a plate supported by a plate receiver R. The load applied to D is
In a balance configured to transmit the levers L ₁ and L ₂ in parallel to each other, combine the outputs of the levers L ₁ and L ₂ , and transmit the output to the load sensor S, a plurality of levers L ₁ and L ₂ are mutually connected. A lever mechanism (including the elastic fulcrums J ₃ and J ₄ of the levers L ₁ and L ₂ ) connected by the elastic connecting portions J ₁ and J ₂ , and an elastic mechanism connecting the lever mechanism and the tray support R the connecting portion _{J 5, J 6, J 7} , J 8, and together with pan supporter R and balances respectively fixed to the dish with receiving portions a _R and the base mounting portion a _B the base B of hollowed each a plate member formed And two plate-like members (first and second mechanism plates) 1 and 2 arranged in the same shape and in parallel with each other, and a tray support is provided between the two plate-like members 1 and 2. It is characterized by the R, the base B, and the connecting members C ₁ , C ₂ being sandwiched and fixed to the respective plate-like members 1, 2.

<Operation> The lever mechanism including the levers L ₁ and L ₂ and the elastic connecting portions J _{1 to} J ₈ and the mounting portions A _R and AB to the pan receiver R and the base _B have the same shape and are parallel to each other. Are formed substantially integrally by the two plate-like members 1 and 2 fixed to each other. In other words, each elastic connecting portions J ₁ through J ₈ without assembled to come are manufactured separately L _1, L ₂ and pan supporter R by a high elasticity steel, integrated in the same material as the lever L _1, L _2, etc. It can be formed, and each part expands or contracts evenly when the temperature changes, and the occurrence of drift is small.

<Embodiment> FIG. 1 is a front view of an embodiment of the present invention, and FIG. 2 is a right side view thereof.

In this example, the present invention is applied to the mechanism shown in FIG. 4, and the same functional members are denoted by the same reference numerals.

The components in this embodiment include, in addition to the dish D and the load sensor S, a dish receiver R having first and second mechanism plates 1 and 2 having the same shape and cushions E... A base B is fixed to the balance frame F, two connection members C ₁ and C ₂ , and two support plates 3 and 4.

The first and second mechanism plates 1 and 2 are each formed in the same shape by hollowing out a plate material, respectively, and levers L ₁ and L ₂ , elastic connecting portions J ₁ , J ₂ , connecting these levers L ₁ and L ₂ , respectively. each lever L _1, L ₂ of the elastic support point J _3, J _4, connecting pan supporter dish with receiving portions for fixing sandwich the R a _R, the L ₁ and L ₂ come with this dish with receiving portions a _R The elastic connecting portions J ₅ , J ₆ and J ₇ , J ₈ , a base mounting portion A _B for sandwiching and fixing the base _B , and a roll prevention portion I are integrally formed.

The anti-rolling portion I is an elastic beam having flexible portions formed near both ends thereof, and one end of the elastic beam is
The elastic connecting portions J ₁ , J ₂ , J ₅ , J ₆ , which are portions for restricting the roll of the dish D (dish tray R) by fixing the other end to the base B. and J ₇ and J _8, the flexible portion of each elastic fulcrum J _3, J _4, and roll prevention part,
Each is obtained by forming a constriction in a flat plate base material.

The first and second mechanisms plates 1 and 2 is disposed in parallel to each other, during which pan supporter R, base B, connecting members C ₁ and C ₂ are attached dish receiving portions respectively A _R, base mounting unit a _B, is sandwiched in the other end of the lever L _1, and anti-yaw section I, are fastened to each other by a respective screw or the like. Then, the load sensor S is fixed on the base B, the sensitive part is connected to the lever L _1.

Further, since the other end of the anti-roll device I is rigidly connected to the base B, the other end of the anti-roll device I and the base B are provided on both outer sides of the first and second mechanism plates 1 and 2. Are provided with support plates 3 and 4 which are screwed respectively.

The material of the first and second mechanism plates 1 and 2 is preferably a material having high strength, a small elastic coefficient, and excellent spring characteristics. Specifically, for example, an aluminum alloy such as duralumin is suitable. ing. Further, as a forming method, a method in which a large number of plate materials are stacked and cut out by wire-cut electric discharge machining is currently most advantageous in terms of cost. However, the machined surface is deteriorated by the heat of the discharge,
Since the spring characteristics and the like are deteriorated, hysteresis or the like is generated as it is, which is not preferable in terms of performance. It is desirable to remove the deteriorated layer on the surface by etching, electrolytic polishing or the like after cutting.

In addition, the support plates 3 and 4, the plate receiver R, the base B, and the connecting member C
_{For 1} and C ₂ , it is desirable to use the same material as the first and second mechanism plates 1 and 2 or a material having substantially the same linear expansion coefficient.

Further, as the load sensor S, any known load sensor S such as a balanced electromagnetic force generating type, a tuning fork type, a string vibration type, etc. can be used. Since the thickness (softness) is limited to a certain extent, a balanced electromagnetic force generation type sensor based on the null method with small displacement is suitable.

Now, the mechanism operation in the above inventive examples, but is comparable to that of Figure 4, the load acting on the dish D resiliently connecting portions J ₅ from pan supporter R, J ₆ or J _7, J transmitted ₈ to L ₁ and L ₂ come not through, the output of the lever L ₂ are combined is transmitted to the L ₁ come not through the elastic connecting portions J _1, J ₂ on the output of the lever L _1, each lever After being reduced by the ratio, it is transmitted to the load sensor S.

In this embodiment, the adjustment of so-called four-corner errors to adjust the measured values so that there is no difference even when a load is applied to an arbitrary position on the plate D is performed by the first and second mechanism plates 1 and 2. In order to adjust the four lever ratios of the levers L ₁ and L ₂ to the same value, for example, it can be implemented by cutting one of the right and left hatched portions shown in a partially enlarged view in FIG. 3 with a file or the like.

In addition to the embodiments described above, the present invention can be widely applied to an electronic balance having a mechanism for transmitting a load on a dish to a plurality of levers in parallel and then combining and transmitting the load to a load sensor. This kind of mechanism has various variations in the leverage combination method. For example, the mechanism shown in FIG. 5 is for transmitting the load of the pan receiver R to the levers L ₁ and L ₂ and synthesizing these outputs. the lever L ₃ is provided is a method of transmitting the output of the L ₃ to the load sensor S. Further, the one shown in Figure 6, what is called a two-stage, the lever L ₁ a load pan supporter R
Transmitted to the L _2, although the output of the L ₂ to be synthesized is transmitted to the L ₁ is the same as the mechanism of Figure 4, further leverage the output of L ₁
Tell L _3, it is conveyed to the load sensor S to expand the displacement again here (scaled down force).

As shown in FIGS. 1 and 2, the mechanism shown in FIGS. 5 and 6 also includes two levers and elastically connecting parts to each part and a plate, respectively, as shown in FIGS. A pan receiving portion and a base mounting portion for fixing the receiving portion R and the base B are integrally formed, and similarly, the pan receiving portion R, the base B, and a suitable connecting member are sandwiched between the mechanism plates and fixed to each other. The present invention can be applied.

<Effects of the Invention> As described above, according to the present invention, two plate members are hollowed out, and a lever mechanism including a plurality of levers and respective elastic connecting portions, a pan receiver and a base are fixedly attached. The two parts are integrally formed, and the pan, the base, and the connecting member are sandwiched and fixed between the two plate-like members, so that the lever, the elastic connecting part, and the like constituting the mechanism are substantially made of the same material. Since they are integrally formed, no deformation or the like due to expansion or contraction difference of each part due to temperature change occurs, and almost zero drift does not occur.

In addition, the number of parts is extremely reduced compared to the conventional assembly type mechanism, and the number of assembly steps is reduced, and it is also possible to adopt a processing method such as laminating and cutting out many thin plates, greatly increasing costs. Can be reduced.

[Brief description of the drawings]

1 is a front view of an embodiment of the present invention, FIG. 2 is a right side view thereof, FIG. 3 is a partially enlarged view for explaining an example of adjusting four corner errors, and FIG. FIGS. 5 and 6 are explanatory diagrams showing examples of other mechanisms to which the present invention can be applied. 1 1st mechanism plate 2 2nd mechanism plate 3 4 support plate L ₁ , L ₂ Lever D Plate D R Plate support B Base C ₁ C ₂ … Connection members J ₁ , J ₂ , J ₅ , J ₆ , J ₇ , J ₈ … Connection members J ₃ , J ₄ … Elastic fulcrum A _R … Dish receiving attachment A _B … Base attachment

Claims (1)

(57) [Claims] 1. A balance configured to transmit a load applied to a plate supported by a plate receiver to a plurality of levers in parallel, and to combine the outputs of the respective levers and transmit the combined output to a load sensor.
A lever mechanism formed by connecting the plurality of levers to each other with an elastic connecting part, and an elastic connecting part connecting the lever mechanism and the pan receiver are fixed to the pan receiver and the base of the balance, respectively. Along with the pan receiving part and the base mounting part,
Each is constituted by two plate-like members which are formed in the same shape and are parallel to each other and are integrally formed by hollowing out a plate material, and the tray support, the base, and the connecting member are provided between the two plate-like members. An electronic balance, which is sandwiched and fixed to each of the plate members.